Elevator-control system



Oct. 24, 1933. G K HEARN 1,932,038

ELEVATOR comm. SYSTEM Filed Dec. 15, 1931 2 Sheets-Sheet 1 M h7g1.

INVENTOR George K Hear/1,

WITNE5$5 (Jet. 24, 1933. G. K. HEARN ELEVATOR CONTROL SYSTEM Filed Dec.

15 1931 2 Sheets-Sheet 2 All 12 x3 [l'au INVENTOR GeorgeKf/earn.

ATTO

Patented Oct. 24, 1933 UNITED STATES PATENT OFFICE ELEVATOR-CONTROL SYSTEM Application December 15, 1931 Serial No. 581,087

18 Claims.

My invention relates to elevator control systems and has particular relation to control systems for effecting a socalled pre-energization, that is, an energization of certain elements comprising the control system before the closure of hatchway door and elevator car-gate interlock switches but, nevertheless, preventing movement of the elevator car until all of the door and gateinterlock switches are closed.

Under the well known restrictions of safety codes for elevators,,the control systems at present in use commonly, include hatchway door and elevator-car gate interlock switches for the purpose of entirely preventing the operation of the system or any part thereof, until the elevatorcar gate and all the hatchway doors are substantially closed.

Due to the time required for the various electro-magnetic control relays to operate as well as the time required for generator and motor fields to build up to operating values, there is a time lag, amounting to a fraction of a second, between the time that the hatchwaydoor and the car gate interlocks operate, indicative of a safe condition forstarting the elevator car and the time that elevator car actually starts to move.

The total waste of time thus caused during a round trip of travel for an elevator car, particularly in high buildings, is a substantial item to be considered by elevator engineers when an increase in the efficiency and speed of operation of the elevator system is sought.

Under present eccnomic conditions involving keen competition between rival manufacturers, a time saving of only a fraction of one minute during a round trip of an elevator car assumes a commercially important aspect, although, the time saved is comparatively negligible with respect to the total time required for the round trip.

My present invention eliminates the unnecessary waste of time mentioned above, by preenergizing certain elements of the control system; that is, energizing them before the gate and door-interlock switches close so that the elevator car may start to move almost immediately upon the closure of the interlock switches. The control system constituting my invention conforms, nevertheless, to elevator safety codes in the various States because it prevents the movement of the elevator car until the gate and doorinterlock switches are closed.

My invention is capable of applications in various types of elevator driving mechanisms and it is particularly applicable to a variable-voltage or Ward-Leonard type of elevator drive well known in the art.

Therefore, it should be understood that although I have illustrated and described my invention, hereinafter, as applied to a Ward- Leonard system, nevertheless, it is applicable to other systems as well.

Briefly, the Ward-Leonard type of drive comprises a direct-current motor, usually of the separately excited shunt-field type, for moving the elevator car, power being supplied to the armature winding of the motor from a compoundwound direct-current generator driven by another motor either of a direct-current or an alternating-current type. The control for the elevator motor is effected by controlling the sepa-v rately excited shunt-field winding of the directcurrent generator.

In variable-voltage elevator control systems at present in extensive use, neither the relays for controlling the generator field winding nor the generator field winding itself is excited or energized prior to the closure of the elevator car gate and hatchway-door interlocks. Conse quently, it is necessary that the relays be oper- 30 ated, that the generator build up an operating value of voltage and that the field of the elevator motor itself build up sufiiciently to cause the motor to exert a sufficient amount of torque to move the elevator car, between the time that the door and gate-interlock switches free the con--v trol' system for operation and the time that the elevator car actually starts to move.

In my present invention, I operate the control relays controlling the generator field and effect 9. the pre-energization or pm-conditioning of the generator field before the closure of the door and gate interlocks so that the time, ordinarily required in existing control systems after the closure of the door and gate interlocks is reduced by the amount of time required for the operation of the relays and the building up of the generator field. I employ the closure of the door and gate interlocks to eifect the electrical connection of the generator to the elevator motor, by means of 109 a suitable relay in the circuit operable to close in response to the closure of the door and gate interlocks. Thus, until the car-gate and hatchway-door interlocks are closed, the elevator motor itself, in my invention, cannot be energized, and hence the elevator car itself cannot move, before the gate and all doors are substantially closed.

Further novelty of my invention comprises a combination of elements including a car switch on the car itself and mechanical levelingswitches 10 for effecting the final stopping operation. I employ a novel combination of elements in which the operation of the car switch efiects the closing of the car gate and a hatchway door, and also controls the switching connections for effecting the pre-energization of the generator field and the switching connections between the generator armature and the elevator-motor armature. The operation of the car switch is effective to control the energization of the generator-field winding whether or not the car gate and hatchway-door interlocks are closed, but the control of the switching mechanism for connecting the generator to the elevator motor is rendered ineffective until the gate and door interlocks are closed.

Furthermore, I employ a novel combination oi. elements including mechanical leveling switches, in an elevator control system, for effecting the control of the switching connections for the generator-field winding and the switching mechanism for connecting the generator and the elevator motor independently of whether or not the gate and door interlocks are closed.

Still another novel feature of my invention comprises means included in a control system, as above described, for eflecting the pre-energization of the generator field to a value which is different than the value thereof for starting the elevator 6&1.

It is, therefore, an object of my invention to eliminate unnecessary waste of time in the operation of an elevator system.

It is another object of my invention to appreciably reduce the time between the closure of gate and door interlocks and the time that the elevator car actually starts to move, while conforming to existing elevator safety codes which require closure of gate and door interlocks before the elevator car can move.

It is another object of my invention to energize the field winding of a generator, which is employed to supply power to an elevator motor after the manner of the Ward-Leonard system of controlfbefore the closure of the door and gate interlocks so that the time after the closure of the door and gate interlocks, ordinarily required before the elevator car actually starts to move, is reduced.

It is another object of my invention to provide a control system, including a car switch on an elevator car, for effecting a control of the switching connections for the generator-field winding and the switching mechanism for connecting the generator to the elevator motor, the control of the switching mechanism for connecting the generator and the elevator motor being ineffective, however, until the gate and door interlocks are closed.

It is a. further object of my invention to provide a control system for efiecting the control of the switching connections for the generatorfleld winding and the switching mechanism for connecting the generator and the elevator motor by means of mechanical leveling switches, independently or whether or not the gate and door interlocks are closed.

It is a still further object of my invention to effect pre energization of the generator field to a value which is diflerent than the value thereof for starting the elevator car.

Other objects of my invention will be apparent from the following specification when read in connection with the accompanying drawings,

wherein,

Figure 1 is a schematic diagram of an elevator system embodying my invention.

Fig. 2 is a diagrammatic view showing the re lation of the elements comprising the hatchway switches which are employed in the system shown in Figure 1.

Fig. 3 is a diagrammatic view, illustrating the operation of one of the hatchway switches, and.

Fig. 4 is a control diagram illustrating the operation of a motor employed for opening and closing the elevator-car gate and any hatchway door aligned therewith.

Referring to Fig. 1, my system of control comprises a variable-voltage or Ward-Leonard type of drive consisting of a direct current elevator driving motor M, provided with a separately excited shunt-field winding M), a compound-wound direct-current generator G for supplying power to the motor M, the generator G being provided with a separately excited shunt-field winding GF, a series field winding GSF, and a demagnetizing field winding GAF, and a motor DM illustrated as of a three-phase induction type for driving the generator G.

The shunt-field winding Mf of motor M is shunted by a limiting resistor r and is in series with control resistors 1'1 and r2. The armature winding Ma of the motor M is connected in a loop circuit in series with the armature winding Go of the generator G, the series field winding GSF of the generator G and a switch constituted by contact members a of a relay 7. The loop circuit is closed when the relay '7 is operated.

The motor DM is energized from the threephase supply conductors m, n, 0, through a suitable switch 11.

The demagnetizing field winding GAF, provided for the generator G, is connected across the terminals of the armature winding Ga, in series with a limiting resistor R and a switch constituted by the contact members of a relay GRl. The purpose of the field winding GAF is to set up a counter-magnetic flux in the field coils of the generator G in order to reduce the residual magnetism therein to zero and prevent the generation of any voltage by the generator G when the relay GRl is actuated to close its contact pose of controlling the direction of current fiow through the field winding GF whereby a reversal of direction of rotation of the elevator motor M and a reversal of direction of movement of the elevator car itself may be effected.

A driving drum D driven by the motor M, is adapted to move an elevator car C in a hatchway by means of a supporting cable Ca which connects the car and a suitable counter weight Cw and which extends around the device.

An electro-magnetically operated brake B of well known construction is provided for the motor M, and comprises a solenoid Bs for releasing the brake shoe from the brake drum thereof and a spring member (not shown) for automatically resetting the brake by effecting a. re-engagement Ju i of the brake shoe and brake drum, when the solenoid Be is deenergized.

A plurality of hatchway door interlock switches d and a car gate interlock switch g of well known construction are provided for effecting the energization or an interlock, relay 38 when all the doors and the gate are substantially closed. An emergency push-button switch ES is provided for shunting the door and gate switches d and g, for the purpose of actuating relay 38 under emergency conditions, that is, even when all the doors and the gate are not substantially closed. It may be disposed in any suitable place, as, for example, on the elevator car itself.

A car switch CS, of any suitable construction, is provided for closing the doors and the car gate and for controlling the stopping'starting, speed, and direction of movement of the elevator car. As illustrated, in Fig. l, the car switch CS comprises a disk ordrum member 20 having oppositely disposed sector members 21 and 22 thereon and provided with a handle 23 for rotating the member 20 about its central axis to a limited extent in either direction, as determined by the up direction stop Us and the down direction stop Ds. The sector 21 is provided with two arcuate insulated conducting segments 24 and 25. A pair of stationary contact or brush members 26, which are connected directly to one of the conductors L2 of the supply circuit conductors L1 and L2, are provided for engaging the segment 24 and maintaining a continuous connection 7 thereof to the supply conductor L2. Upon the requisite amount of angular movement of the handle 23, the contact members 26 are connected either to stationary contact members U2 or D2, respectively, for opposite directions 02 rotation of the handle. The switches comprising contact members 62 and D2, are for the purpose of effecting the energization of relays 4i and 42 respectively.

The actuation of relay 41 effects the energization of relays l and 3, whereby current is caused to fiow through the generator field winding G-F such a direction as to cause the motor M to move the elevator car upwardly.

Upon the actuation of relay 42, the relays 2 and 4 are energized and a reversed direction of movement of the elevator car is effected.

A of contact members 27 are disposed sta tionarily in engagement with the segment 25 for effecting a continuous connection of the segment with the supply conductor L1. A pair of contact members U1 and D1 are spaced an equal angular distance on opposite sides of the contact members 27 for connection to the latter by a sufficient angular rotation of the segment 25 in the proper direction. The disposition of the contact members U1 and D1 is such that upon a rotation of the handle in opposite directions from a neutral position, the switches comprising the contact members U1 and D1 are closed respectively to effect the energization of a relay 45, which relay, as shown in Fig. 4, effects the energization of a door motor 10 to close a hatchway door and the elevator car gate. The mechanism associated with motor 10 may be organized in accordance with any one of a plurality of well-known arrangements, but is preferably organized in the manner disclosed in a copending application. Serial No. 452,231, filed May 14, 1930, by Harold V. McCormick, and assigned to the Westinghouse Electric Elevator Company. As described in that application, the door-operating motor is mounted control. diagram is shown for purposes of illus tration to describe in detail the control of the door motor. The motor 10 is illustrated as of a series type, either alternating or direct current, comprising an armature winding ll and a field winding 12. A reversal of direction of rotation of the motor 10 is effected by reversing the direction of flow of current through the field winding 12 and the relay 45 is provided for this purpose. Closing and opening limit switches 33 and 34, of any suitable type, are employed in associative connection for the purpose of stopping the motor 10 when the door and gate are completely closed or completely opened, respectively. The relay 45 comprises the normally open switch-=contact members a and b and the normally closed switch-contact members 0 and (1, each of the contact members being adapted to close a switch. In the deenergized position of relay 45, as shown in Fig. 4, the contact members c and d are closed and the circuit for energizing' the motor armature 11 and field winding 12 extends from one terminal LLl of'a source of supply through conductors 13 and 14, contact members c of relay 45, conductors 37 and 15, field Winding 12, conductors 39 and 40, limit switch 34, conductor 16, contact members d of relay 45, conductors 1'7 and 43, armature winding 11 and conductor 44 to the other terminal LL53 of the source of supply. When the hatchway door and the car gate are completely opened the limit switch 34 opens to stop the motor 10.

When the relay 45 is energized the contact members a and 12 thereof close a circuit for energizing the field winding 12 in the opposite direction and thus cause the motor to rotate in the opposite direction and efiect the closing of the door and gate, This circuit extends from terminal LLl through conductor 13, contact members a of relay 45, conductor 45, limit switch conductor field winding 12, conductors l5 and 47, contact members b of relay 45, conductor armature winding 11 and conductor 44 to terminal LL2. When the door and gate are completeiy'closed, the limit switch 33 opens to stop the motor.

A pair of contactv members or brushes 28 are stationarily disposed in engagement with a conducting segment 29 on the sector 22 of the car switch OS for continuously connecting it to a supply conductor L3 which is connected to the supply conductor L2 through contact members of relay 38 when the latter is energized.

Disposed, respectively, at equal angular dis tances on opposite sides of the contact members 23, are stationary contact members U3 and D3, and a rotation of the sector 22 through an angle causes the segment 29 to connect either the contact member U3 or D3 to the contact members 23, 1

shunt the resistors R3 and R4 and thus effect acceleration of the motor M.

A pair of stationary contact members U4 and D4 are disposed at equal angular distances on opposite sides 01' the contact members 28, the angular distance being greater than the angular distance between the contact members 28 and the contact members U3 and D3 so that a greater angle of rotation 01' the sector 22 is required to cause the segment 29 to connect either of the contact members U4 or D4 to the contact members 28.

The connection of either of the contact members U4 and D4 with the contact members 28, closes a circuit for energizing a relay GRA and a reLay 56. When relay GR4 is thus actuated, its contact members a short-circuit the resistor R5 whereby the final step in the acceleration of the motor M is effected.

The actuation of relay 56 effects the actuation of a relay 55 which causes the resistor R4 to be included with the resistor R5 in the short circuit connection effected by the contact members a of the relay (3R4 for the purpose of obtaining proper deceleration of the elevator car and thus preventing the elevator car from passing the floor at which it is to stop. This particular feature of my invention is already known in the art and does not constitute a part 01 my present invention.

Although any suitable means may be employed for slowing down the elevator car and stopping it at a desired floor, I prefer to employ inductor relays 2L, 2D, 3L, 3D, 4L, 4D for eifecting slow-down and to employ mechanical cam-operated levelling switches UL and DL ior eflecting the final stopping of the elevator car at the desired floor.

For purposes of clarity, I have illustrated the inductor relays 2L, 3L and 4L in Fig. 1 and the relative positions, at one floor, of the up-stop inductor plates 2U, 3U and 4U and the down-stop" inductor plates 2D, 3D and 4D for the relays 2L,

' 3L and 4L, respectively, in Fig. 2. Although the inductor plates for only one floor are shown, it should be understood that each of the other floors is provided with similar sets of plates except the upper terminal floor which is provided only with up-stop" inductor plates and the lower terminal floor which is provided only with down-stop" inductor plates.

The inductor relays may be of any suitable type but are preferably of the type described in the copending application of Harold W. Williams, Serial No. 279,771, filed May 22, 1928, and assigned to the Westinghouse Electric and Manufacturing Company, the construction and operation of which may best be understood by reference to Fig. 3 in which one is diagrammatically shown.

Referring to Fig. 3, any of the inductor relays, as for example, relay 4L, comprises a magnetic structure 4a, of T-shape, having a central core portion 42) and a. pair of small lugs or projections 4c extending from the end thereof on opposite sides. A pair of armatures 4d and 4c, of magnetic material, are pivoted to the magnetic structure 4a in juxtaposition to the lugs 40. Each of the armatures 4d and 4c is provided with a contact member for engaging a separate stationary contact member. The contact member on armature 4d and its associated stationary contact member will hereinafter be designated as contact members 4UL and the contact member on armature 4e with its associated stationary contact member will be designed as contact members 4DL.

The armatures 4d and 4e are biased by any suitable means, such as a spring, to a position in which their contact members respectively engage their associated stationary contact members. When an armature is pivoted away from its associated stationary contact member, the switch constituted thereby is opened.

An energizing coil or winding 4w is mounted on the core portion 4b of the magnetic structure 4a. The magnetic structure 4a and the armatures 4d and 4e constitute a divided magnetic circuit oi two branches both of which are normally incomplete because of the large air gaps between the upper portion of the magnetic structure and the armatures.

The inductor relays 2L and 3L are provided with contact members 2UL and SUL, respectively, which correspond to contact members 4UL of relay 4L and are also provided with contact members 2DL and 3DL, respectively, which correspond to contact members 4DL of relay 4L. The energizing windings for relays 2L and 3L, corresponding to the winding 4w for relay 4L, are designated respectively as 2w and 3w.

The operation of any of the relays is as follows, relay 4L being taken as an example: As long as the winding 4w is deenergized, the armatures 4d and 4e remain in their biased positions with their contact members engaging their respectively associated stationary contact members. Upon the energization of the winding 4w, as by the closure of a switch 48 connecting the winding to a suitable source of energy such as the batery 4B, a magneto-motive-iorce is impressed on the magnetic circuit of the relay. Because of the large air gap between the armature and the opposite ends of the magnetic structure 4a, the magnetic flux set up in he relay is insuflicient to cause a pivotal movement of the armatures. If a branch of the magnetic circuit is completed, however, as by movement of the relay into a position adjacent to an inductor plate 4U, the corresponding armature 4d pivots, against the force exerted by the biasing means, into a position to engage the corresponding lug 40, thus effecting the disengagement of conact members 4UL. As the relay passes the inductor plate and moves away therefrom, the armature 4d does not return to its biased position because of the magnetic attraction exerted thereon by the lug 4c.

In a similar manner, assuming the coil 4w to be energized, if the second branch of the magnetic circuit is completed by movement of the relay into a position adjacent a second inductor plate, the armature 4c is pivoled into a position in engagement with its corresponding lug 4c and, when the relay moves away from the inductor plate, the armature 4e does not return to its biased position because of the magne ic attraction exerted thereon by the lug 40 with which it is in engagement.

When the winding 410 is deenergized by opening the switch 48, the magnetic attraction exerted by the lugs 40 upon the armatures 4d and 4c is insuflicient to overcome the force exerted by the biasing means and the armatures are returned to their biased positions.

It the winding 4w of the relay is deenergized, movement of the relay into a position adjacent an inductor plate is ineffective to cause a separation of the contact members 401. or 4DL.

It will, therefore, be seen that a separation of the con act members 4UL and 4DL is etlected only when the winding 420 is energized and the relay is moved into a position adjacent a corresponding inductor plate.

' The levelling switches UL and DL are of the type which may be actuated to close contact members either by the engagement with a cooperating cam of a roller carried at the end of an operating arm, or by energizing the coil of an electro-magnetic retiring mechanism.

Referring to Fig. 1, the switch UL comprises an operating arm Ua which is bent into the shape of an obtuse angle and pivoied at the apex of the angle on a suitable member disposed on the elevator car. On one end of the operating arm Ua which extends into the hatchway, is rotatably mounted a roller Ur and on the other end there is provided a pair of insulaled contactmembers, disposed in spaced relation, each for engaging a separate stationary contact member associated therewith. Hereafter, one set of these contact members will be designated as contact members ULl and the other set as contact members UL2. The arm Ua is biased by any means, such as a spring Ud, to a position in which the contact members ULl and UL2 are respectively separated. A retiring or retracting coil Uw is provided for raising a plunger, pivotally attached to the operating arm at a point between the contact members thereon and the pivolal point of mounting thereof, whereby when the coil is energized, the contact members on the operating arm move to engage their respectively associated stationary contact members against the force exerted by the spring Ud.

The switch DL is correspondingly constructed so that a pair of contact members on an operating arm Dc are respectively associated with a a pair of stationary contact members, which sets of contact members will be hereafter designated as contact members DLl and DLZ.

Referring to Fig. 2, the switches UL and DL are mounted upon the elevator car C in such position that the rollers Ur and Dr extend into positions such that they may engage, respectively, cams 1U and 1D stationarily mounted in the hatchway adjacent each floor, when the car moves past the cams, unless the rollers are retired from their projecting positions due to the fact that the coils Uw or Dw, respectively, are energized.

The piston of each pair of cams 1'0 and 1D with respect to the associated floor, as shown in Fig. 2, is such that when the elevator car is substantially level therewith the rollers Ur and Dr are not in engagement with the raised surfaces of their respectively associated cams.

The operation of the levelling switches UL and BL is as follows:

The retiring coils Uw or Dw are energized so long as the elevator car is moving pastfloors at which it is desired that the car should not stop and therefore, the rollers Ur and Dr are retracted to a position in which they move freely past the cams 1U and 1D. However, when the elevator car approaches a floor at which it is desired it should stop, after being slowed down in successive steps by the operation of the inductor relays, the coils are automatically deenergized. The deenergization of the retiring coils takes place when the elevator car is in such a position in the hatchway with respect to the floor at which it is desired it should stop, that the raised surfaces of the cams 1U and. 1D engage the rollers 'Ur and Dr respectively to .maintain the operating arms in such position that the contact members ULl, UL2, and IJLl, DLZ are maintained in engagement with each other.

When the elevator car attains a position such that the floor thereof is at the level of the floor at which it is desired the car should stop, the roller Ur rolls down the inclined surface of thecam from the raised surface thereof and the spring Ud effects the disengagement of the contact members ULl and ULZ whereby the final stopping of the elevator motor is effected.

When the elevator car is ascending the deenergization of the retiring coil on the switch DL is effected when the roller Dr is not engaged by the raised surface of the cam 1D. Therefore, the operating arm of that switch is biased into a position whereby the contact members DLl and DL2 are separated. However, because the contact members DLl and DL2 are not included in the effective operating circuit at the time the car is ascending, the separation of the contact members on the switch DL is of no effect.

Conversely, when the elevator car is descending, the contact members DLl and DL2 of the switch DL are maintained in engagement with each other because the roller Dr is engaged by the raised surface of the cam 1D, whereas the contact members ULl and UL2 of the switch UL are separated because the roller Ur does not engage the raised surface of the cam 1U. The contact members 1 ULl and UL2, not being included in the effective operating circuits in use for the down direction of travel of the elevator car, the separation of the contact members ULl and UL2 is of no effect.

The energizing circuit for the retiring coils Uw by the separation of the contact members 2UL or 2DL on the inductor relay 2L for the up and down directions of movement of the elevator car, respectively, and therefore, the retiring coils are deenergized after the elevator car has passed its final step of deceleration effected by the separation of contact members 2UL or 2DL.

The operation of my invention, as exemplified by the control diagram, shown in Fig. 1, will be best understood by following through in logical sequence thevarious steps in the operation thereof from the time the elevator car is ready to start until the time that it is completely stopped at a desired floor and the hatchway door and car gate are opened to allow passengers to leave the car.

Let it be assumed that the elevator car C is at i a fioor, such as the lower terminal floor, and that the gate thereon and the hatchway door at that floor are completely open to allow passengers to enter the car. Let it be assumed further, that all the waiting passengers have entered the car and that it is desired to start upwardly, and to stop at any desired floor. The operator in the car rotates the handle 23 on the car switch CS through an angle in the proper direction, such direction, in Fig. 1, being a clockwise direction. 1': The rotational movement of the sectors 21 and 22 effected thereby is stopped by up-stop member Us in which position the contact member U1, is con nected to the contact members 27, the contact member U2 is connected to contact members 26,

and the contact members U3 and U4 are connected to-contactmembers 28, as previously described.

The connection of the contact member U1 with the contact members 27, by the connecting segment 25, closes a circuit for energizing the door operating relay to effect the closing of the hatchway door and car gate, which circuit extends from supply conductor LI through conductors and 61, a contact member 27; segment 25, contact member U1, conductors 62 and 63, coil of relay 45, and conductor 64 to supply conductor L2.

The motor 10 is thus energized to effect the simultaneous closing of the hatchway door and the elevator car gate. The control circuits for the motor 10 have been previously traced and it is deemed unnecessary to repeat such description.

The connection of the contact member U2 to a contact member 26, closes a circuit for energizing the relays 50 and 41, the closing of the contact members of relay 41 eflecting the energization of the direction relays 1 and 3 whereby the generator field winding GE is connected across the supply conductors L1 and L2 in series with the resistors R1, R2, R3, R4 and R5.

The circuit for energizing the relays 50 and 41, extends from supply conductor L1 through conductor 65, the coil of relay 50, conductor 66, the coil of relay 41, conductor 67, contact member U2, segment 24, contact members 26 and conductor 68 to supply conductor L2.

The cnergization of relay 50 eflects the opening or the normally closed contact members of that relay to open the already opened circuits for energizing the coils 2w, 3w, and 4w, 0! the inductor relays and has, therefore, no immediate eiiect.

The energization of the relay 41 effects the closing oi the contact members of that relay which eflect the closing of a circuit for energizing the "up" direction relays 1 and 3 and relay 5, which circuit extends from supply conductor L1 through conductor 69, contact members of relay 41, conductor 70, coil 0! relay 1, conductor I1, coil of relay 3, conductor 72, normally closed contact members c of "down direction relay 2, conductor 73, coil of relay 5, and conductor 74 to supply conductor L2.

The energization of relay 5 effects the closing, of normally open contact members a and b of that relay, the former closing a shunting circuit around the resistor r1, in series with the field winding M! of the main motor M, whereby the field is strengthened, and the latter contact members closing a circuit for energizing relay 6R1. The circuit for energizing relay GRl extends from supply conductor L1 through conductor 75, coil of relay GRI, conductor '76, contact members I; of relay 5, and conductor 7'7 to supply conductor L2.

The energization of relay GR1 eflects the opening of the contact members or that relay which open the circuit connected across the terminals 0! the generator armature Ga and including the demagnetizing field winding GAF of the generator G. The winding GAF is thus rendered ineffective to produce a demagnetizing effect.

The contact members of relay 3 and the contact members a of relay 1 when simultaneously closed, close a circuit for energizing the generator field winding GF, which circuit extends from supply conductor L1 through conductor 78, contact members do! relay 1, conductor 79, field winding G1", conductor 80, contact members of relay 3, conductor 81, resistors R1, R2, R3, R4 and R5 in series and conductor 82 to supply conductor L2.

The resistor R1 is employed in series with the resistors R2, R3, R4, and R5 to limit the current through the generator field winding GF upon pre-energization to a value which is lessthan the value of the current therethrough at the timethe car A relay 8 is employed to short-circuit the resistor R1 after the door and gate interlock switches d and g are closed and the car is ready to start, and thus the value of current through the generator field winding GF is greater at the time the car is ready to start because only the resistors R2, R3, R4, and R5 are employed to limit the current. It should be understood that by causing the contact members of relay 8 to short-circuit the resistor R1 during pre-energization and by causing the contact members of relay 8 to be opened and thus open the short-circuit connection around the resistor R1, after the door and gate interlock switches have closed, the pre-energization value of current through the generator field winding GF may readily be made greater than the value of the current through the generator field winding at the time the car is ready to start as might be desirable in some cases. Furthermore, it should be understood that by omitting the resistor R1 and its control relay 8 from my control system, the pre-energization value of current through the generator field winding and the value of current therethrough at the time the car is ready to start may be made the same.

I prefer, however, to employ the resistor R1, in order to avoid the possibility of suddenly and abruptly starting the elevator car without smooth acceleration which may result if excessive voltage is impressed on the armature winding Ma 0! the motor M from the armature winding Ga of the generator G.

In well known elevator control systems, the field winding M] of the motor M is continuously energized as long as the supply conductors L1 and L2 are connected to the source of supply. Ordinarily a resistor is connected in series with the field winding M for the purpose of reducing the power consumption to a minimum while maintaining the field continuously energized.

The resistor 1'2 is provided for this purpose as will be explained in greater detail hereinafter.

In addition to the resistor r2, I have provided a resistor 11, also connected in series with the field winding Mf of the motor M when the latter is not in operation, and I cause it to be shunted out of the field winding circuit upon the preenergization of the generator field winding GF thereby strengthening the motor field. It has been found that a strengthening oi the field o1 motor M at the time of pre-energizing the generator field winding GF improves the operation and tends to prevent overshooting of speed.

The contact members a of relay 5, having been closed by the energization of relay 5, as previously described, close a short-circuit connection around the resistor 71 and thus, by shunting it out of the motor field Winding circuit, effect a strengthening on the field of the motor M.

Upon energization of relay 1, contact members 0 thereof close a circuit or energizing a relay FRI which in turn, by the CIOSlIlgF, of its contact members thereof, closes a short-circuit connection around the resistor 12 whereby the field of the motor M is strengthened to its normal op- If crating value.

The circuit for energizing relay FRI extends from supply conductor L1 through conductor 83, contact members 0 of relay 1, conductor 84, contact members (now closed) of relay FR, conductor 85, coil of relay FRI, and conductor 86 to supply conductor L2.

It should be understood that all the foregoing operations occur during the time that the hatchway door and car gate are closing, that is, before they are substantially closed. It will thus be clear that the time required for the operation of the various above-mentioned relays and for the building up of the generator field GE is consumed before the hatchway door and car gate interlock switches 11 and g are closed, and, therefore, that the subsequent time required before the elevator car starts to move is thereby lessened by this amount of time.

Now let it be assumed that the door interlock switches d and the gate interlock switch g have been closed.

The switches d and g, when closed, close a circuit for energizing relay 38, which circuit extends from supply conductor L1 through conductor 87, the door interlock switches d in series, conductor 88, gate switch 9, conductors 89 and 90, coil of relay 38 and conductor 91 to supply conductor L2.

The emergency. switch ES is connected in parallel with the switches d and g for the purpose of permitting emergency operation of the elevator switches, such as during testing operations, without the door and gate interlock switches being closed. However, in the sequence of operations now being described the emergency switch ES is not employed.

The contact members of relay 38 when closed by the actuation of the relay, close two separate circuits for energizing respectively, pick-up coil 7? of relay 7 and the coil of relay 36.

Relay 7 is provided with two windings or coils, namely, the pick-up coil 7? and the holding coil 7H, the former having the requisite strength, upon being energized, to actuate the relay but the latter being incapable of exerting a force suflicient to initially actuate the relay. Once the relay is actuated or picked up by the energization of the coil 7P the coil 7H, however, exerts a surficient force, when energized, to maintain the relay in an actuated position although the coil 7? is deenergized.

The circuit for energizing coil 7P of relay 7 extends from supply conductor L1 through conductor 97, coil 7P, conductor 98 and contact members of relay 38 to supply conductor L2.

The circuit for energizing relay 36 extends from supply conductor L1 through conductor 150, contact members 6 of relay 1, conductor 151, contact members ZUL of inductor stopping relay 2L, conductor 152, coil of relay 36, conductor 153, supply conductor L3 and contact members of relay 38 to supply conductor L2.

The energization of relay 36 effects the closing of contact members a, b and 0 thereof. The contact members a of relay 36 when closed, close a short-circuit connection around the resistor R2, thus causing the energizing current flowing through the generator field winding GP to increase and effect a building up of the voltage of the generator G to a value greater than the preenergization valve thereof..

The contact members 1) of relay 36 are con- .nected in parallel with the circuits including con tact members U1 and D1 on the car switch CS and when closed, establish a holding circuit for the coil of the door-operating relay is for the purpose of preventing the operation of the door-operating motor 30 to open the door and gate. The holding circuit extends from supply conductor L1 through conductors 60 and 92, contact members I) of relay 36, conductor 63, coil of relay 45 and conductor 64 to supply conductor L2.

The contact members c of relay 36, when closed, close a circuit for energizing the retracting coils Uw and Dw of the levelling switches UL and DL,

respectively, which circuit extends from supply conductor L1 through conductor 93, coil Uw, con ductor 94, coil Dw, conductor 95, contact members c of relay 36, conductor 96, supply conductor L3 and contact members of relay 38 to supply conductor L2.

, The rollers UT and D1. on the switches UL and DL, respectively, are thus retracted and the operating arms of the switches moved to effect a closing of the contact members ULl, U112, DLl and DL2. The switch comprising contact members ULl is connected in parallel with the contact members of relay 41 and when the former are closed they establish a holding circuit for maintaining the relays l, 3 and 5 energized independently of whether the contact members of re lay 41 are open or closed.

As previously described, the coil 7P of relay 7 was energized by the closing of thecontact members of relay 38, resulting in the closure of contact members a and b of relay 7. The contact members a of relay 7 when closed, close the loop circuit connecting the motor armature winding Ma in series with the generator armature winding Ga, and thegenerator series field winding GSF, whereupon the motor is actuated to start moving the car upon the release of the brake B by contact members I) of relay 7 effected in a manner immediately hereinafter described.

The contact members I) of relay 7 close a plurality of circuits for energizing, respectively, the brake solenoid Bs of the brake B, the holding coil 7H of relay 7, the coil of relay 32, and the coil of relay 8.

The circuit for energizing the brake solenoid Bs and the holding coil 7H extends from supply conductor L1 through conductor 99, contact members b of relay 1, conductor 100, thence in parallel through two branches, one branch comprising coil 7H, conductor 101, brake solenoids Bs, conductor 102, and the other comprising the discharge resistor sR, thence through conductor 103, contact members I) of relay 7 and conductor 104 to supply conductor L2.

The energization of the brake solenoid Be releases the brake B, associated with the elevator motor M, thus permitting the motor M to rotate and thereby move the elevator car C.

The discharge resistor 8R which is connected in parallel with the holding coil 7H and the brake solenoid Be, as previously described, is provided for the purpose of permittinga circulating discharge current to flow through itself, the coil 7H and the solenoid Bs for a short interval of time after the generator field winding is deenergized. The holding of relay 7 in an actuated position for a short interval of time after the generator field is deenergized delays the opening of contact members a of relay 7 a suiiicient time to allow the current between the generator and motor armatures flowing therethrough to be reduced to a negligible amount so that, when the contact members open, serious arcing is prevented. The gradual deenergization of the solenoid as 'eiiected by the discharge current dying out, causes the brake B to be applied gradually in view of the fact that the spring for returning the brake shoe into engagement with the brake drum gradually overcomes the force exerted by the solenoid Be. A smooth braking effect is thus secured. 1

The circuit for energizing relay 32' extends from supply conductor L1 through conductor 99, contact members I) of relayl, conductors 100, 105 and 106, coil of relay-32, conductors 107 and 103,

contact members b of relay '7 and conductor 104 to supply conductor L2.

The contact members of relay 32 are closed by the energization of the relay to partially close a circuit for energizing the windings 2w, 3w, and 4w of the inductor relays 2L, 3L, and 4L, respectively, the circuits being still open due to the fact that the contact members of relay 50 are open. The actuation of relay 32, therefore, has no immediate affect other than that mentioned.

The circuit for energizing the coil of relay 8 extends from supply conductor L1 through conductor 108, coil of relay 8, conductors 109, 102 and 103, contact members b of relay 7 and conductor 104 to supply conductor L2.

The contact members of relay 8, when closed, close a short-circuit connection around the resistor R1 and thus the current through the generator field winding GF is increased to effect an increase in the voltage oi. the generator G.

As above mentioned, the closing of contact members a of relay 7 closes the loop circuit conmeeting, in series, the armature winding Ga of the generator G, the series field winding GSF of the generator G and the armature winding Ma of the elevator motor M, whereupon the voltage, built up in the generator armature winding at this time, is impressed on the armature winding Me of the motor M.

The motor M thus starts to rotate at the slow starting speed and rotates the drum D to move the elevator car upwardly.

As will be recalled, the contact members U3 and U4 have been connected all this time to the contact members 28 due to the fact that the handle 23 of the car switch CS has been held by the operator in its extreme position.

A circuit for energizing the relay GR3 is completed by the connection of the contact member U3 to the contact members 28 when the doors and gate interlock switches d and g are closed and the relay is now actuated to close its contact members a and b and open its normally closed contact members 0.

The circuit for energizing the relay GR3 extends from supply conductor L1 through conductor 110, contact members I of relay 1, conductor 111, contact members 3UL of the inductor relay 3L, conductor 112, coil of relay (3R3, conductors 113, 114 and 115, contact member U3, segment 29 and contact members 28 of car switch CS, conductors 116 and 117, supply conductor L3, and contact members of relay 38 to supply conductor L2.

The closing of contact members a of relay-6R3 closes a short-circuit connection around the resisters R3 and R4 due to the fact that the normally closed contact members of the relay 55 are closed. The strength of the current flowing through the generator field winding GE is thus further increased, and the voltage generated in the armature winding Go of the generator G still further increased. Due to the increased potential thus caused to be impressed on the motor armature winding Ma, the motor increases its speed which results in an increased speed of travel of the elevator car.

The closing of contact members b of relay GR3 establishes a holding circuit for the coil of relay GR3 to maintain it energized independently oi the position of the handle 23 on the car switch CS, which circuit extends from supply conductor L1 to the coil of relay GR3, as previously traced, thence through the coil of relay (3R3, conductors m 113 and 114, contact members b of relay GRS,

conductor 118, supply conductor L3, and contact members of relay 38 to supply conductor L2.

The opening of contact members of relay GR3 partially opens the circuit for energizing the coil 2w of the inductor relay 2L, which circuit is also, at this time, already partially opened by the open contact members of relay 50.

Assuming that the car switch handle 23 is held in its extreme position and that a travel 0! the car to a remote floor is contemplated, the voltage generated by the generator G is sufllcient at this time to actuate a voltage responsive relay 35, connected across the terminals of the motor armature winding Ma.

The contact members of relay 35, when closed, by the actuation thereof, complete a circuit, already partially closed by the connection of the contact member U4 on the car switch CS to the contact members 28 thereon, for energizing the relays GR4 and 56.

The circuit for energizing relays GEM and 56 extends from supply conductor Ll through conductor 119, contact members 9 of relay 1, conductor 120, contact members 4UL of inductor relay 4L, conductor 121, contact members of re lay 35, thence dividing into two branches going through one branch by way of conductor 122, col of relay 56, conductors 123 and 124 to the point 125 and going through the other branch by way of conductor 126, the coil of relay GR4 and conductor 127 to the point 125, thence through conductor 128, contact member U4, segment 29 and contact members 28 of the car switch CS, and conductors 116 and 117 to supply conductor L3 which is connected to supply conductor L2 through contact members of relay 38.

The actuation oi relay 6R4 closes the contact members 0 thereof and opens its contact memhers I). Closing of the contact members a of relay 6R4 closes a short-circuit connection around the resistor R and thus the final step in the acceleration of the car is effected because the generator field winding GF is now energized to its fullest extent and the generator G is impressing a maximum voltage on the armature winding Ma of the motor M.

The opening of contact members I) of relay (3R4 partially opens the energizing circuit for the coil 3w of the inductor relay 3L which circuit is also partially opened at this time by the open contact members of relay 50.

The actuation of relay 56 closes its contact members a and b, the closing of the latter contact members establishing a holding circuit for maintaining the coils of relays GR4 and 56 energized regardless of the position of the car switch handle 23. The contact members b of relay 56 are connected in parallel with the switch comprising contact member U4 and the contact members 28 on the car switch CS between the point 125 and supply conductor L3.

The closing of contact members a of relay 56 closes a circuit for energizing the coil of relay which circuit extends from supply conductor L1 through conductor 99, contact members b of relay 1, conductors 100, 105, and 129, coil of relay 55, conductor 130, contact members a of relay 56 and conductor 131 to supply conductor L2.

The actuation of relay 55 closes its contact members a and c, and opens its contact members I). The contact members c, when closed, establish a holding circuit for maintaining the coil of relay 55 energized and are connected in parallel with contact members a, of relay 56, the ener- V and continues nesaoes g'izing' circuit for the coil of relay being otherwisethe same as previouslytraced. I

The closing of contact members a and the opening of contact members I) of relay 55 changes the tap connection to the resistors R3 and R4 and renders only the resistor R3 subject to short-circuit by the contact members a of relay GR3 and further renders the resistors R4 and R5 subject to short-circuit by the contact members a of relay (3R4.

The reason for this change in tap connection to the resistors is that, upondeceleration, it has been found necessary to deenergize the generator field winding GF more rapidly in order to prevent the elevator car from overtravel. The change in tap connection to resistors R3, R4 and R5 efiected by the contact members a and b of relay 55, is, at this time, of no immediate effect other than the conditioning of the deceleration circuits for subsequent deceleration of the elevator car.

When the voltage generated by the generator G is a maximum, a voltage responsive relay 31 having its coil connected across the armature winding Ma of the motor M, is actuated to close its contact members. The contact members of relay 31 when closed, close a circuit for energizing the coil of relay FR, which circuit extends from supply conductor L1 through conductor 119, contact members g of relay 1, conductor 120, contact members eUL of inductor relay 4L, conductor 121, contact members of relay 35, conductors 122 and 132, contact members of relay 31, conductor 133, coil of relay FR, conductor 124 to the point 125 and thence through the contact members I) of relay 56, supply conductor L3, and contact members of relay 38 to supply conductor L2.

The actuation or relay FR causes its contact members to open and the opening of the contact members opens the circuit, previously traced, for energizing the coil of relay M31.

The deenergization of the coil of relay FRl causes the contact members thereof to open and remove the short-circuited connection across the resistor T2 in series with the field winding M) of the motor M.

The insertion of the resistor T2 in the field winding circuit thereof weakens the field of the motor M, and in accordance with the characteristic action of a shunt motor upon the weaken ing of the field, it rotates at a slightly higher speed, which speed is the highest speed attainable by the elevator car.

The elevator car now runs at its highest speed to do so as long as the operator holds the car switch handle 23 in its extreme position.

Let it now be assumed that the operator desires to stop the car at a remote floor, for example, floor ten. He centers the car switch handle 23 when the car is a distance away from the floor at which it is desired to stop, which is slightly greater than the distance of the inductor stopping, plate 4U associated with the particular floor at which it is desired to stop. The distance of the inductor stopping plate 4U from the floor with which it is associated depends, of course, upon the highest speed of travel of the elevator car because the greater the speed of the elevator car, the greater is the distance required for smoothly and gradually decelerating the car.

Assuming then, that the operator has centered the car switchhandle 23 at the proper time, to effect the stopping of the elevator car at the floor desired, the immediate effect of such centering oi the car switch handle is to deenergize the coils of relays 50 and 41 due to the fact that the segment 24 110 longer connects the contact member U2 on the car switch CS to the contact members 26, whereby the energizing circuit, previously tr ced, for the coils of relays 50 and 41 is openedt i The opening of the contact members of relay ll, caused by the deenergization of the coil th" set, is without effect because, as previously explained, the switch comprising the contact members of the levelling switch UL, connecte in parallel with the contact members of relay 41, is maintained closed at this time due to the fact that the retracting coil Uw is energized.

The deenergization of the coil of relay 50 causes the contact members of the relay to reclose and thereby close a circuit for energizing the coil or" inductor relay 4L, which circuit extends from supply conductor Ll through conductor 134, contact members of relay 32 (now closed), conductor 135, contact members of relay 50, conductors 136 and 137, coil 4w of inductor relay 4L and conductor 138, to supply conductor L2.

When the elevator car attains a position in the hatchway in which the inductor relay 4L is adjacent to the inductor plate 4U, the relay operates, as previously described, to separate the contact members dUL and thereby open the circuit, previously traced, for energizing the coils of relays G34, 56 and FR.

The deenergization of the coil of relay FR causes the contact members of the relay to close and thereby reclose the circuit, previously traced, for energizing the relay PR1. The energization of relay PR1 causes the contact members thereof to close and thereby close the short-circuit connection around the resistor T2 in series with the motor field winding M1. The cutting out of the resistor r2 from the field circuit of the motor M strengthens the field and thereby efiects a decrease in the speed of rotation of the motor M in accordance with well known characteristic action of a motor. The elevator car thus starts to slow down.

The deenergisation of the coil of relay 56 is without immediate efiect because the contact members 0 of relay 55 being in parallel with contact members a of relay 56, maintain a holding circuit independent of the position of the contact members a and because the opening or" contact members 21 of relay 56 merely partially opens to a greater extent the circuit for energizing the coils of relays 6B4, 55 and FR already opened by the separation of the contact members l-UL.

The deenergization of relay (3R4 causes the contact members 0!, thereof to open and the contact members b thereof to close. The opening of contact members a of relay GR l removes the short-circuit connection across resistors R4 and R5 and the current through the generator field winding GE is thus reduced to cause a reduction in the generated voltage of the generator G with a consequent reduction in the rotational speed of the motor M and the speed of travel of the elevator car. As previously explained, the amount of change in the energization of the field winding GE is greater for this step of deceleration than for the corresponding step of acceleration in order to prevent the overtravel of the car past the floor at :which it is desired it should stop.

The contact members I) of relay GR4, when closed, close a circuit for energizing the coil 3w of inductor relay 3L, which circuit extends from supply conductor L1 through conductor 134, contact members of relay 32, (now closed) conductor 135, contact members of relay 50, conductors 136, I3"? and 139, coil 310 of relay 3L, conductor 140, contact members b 01' relay GR4 and conductor 141 to supply conductor L2. It will thus be observed that the coils for the inductor relays are energized only at the time required and, therefore, that the power consumption is a minimum.

The elevator car now passes a position in which the relay 3L is adjacent the inductor plate 3U and thereby effects the actuation of the relay, in the manner previously described, to separate the contact members 3UL. The circuit, previously tracedior energizing the coil of relay GR3 is thus opened and the relay is deenergized, which oil'ects the opening of the contact members a and b of the relay and the closing of the contact members e of the relay.

The opening of the contact members a of relay (5R3 removes the short-circuit connection around the resistor R3 inthe circuit of the generator field winding GP, thus effecting a reduction in the generated voltage of the generator and a consequent reduction in the speed of the motor M and the speed oi travel of the elevator car. The opening or the contact members b of relay GR3 is or no eil'ect at this time because the holding circult which it maintains ior energizing the coil of" relay (3R3 has been previously opened by the separation of the contact members 3UL. The contact members 0 of relay GR3 when closed, close a circuit tor energizing the coil 2w of relay 2L, which circuit extends from supply conductor L1, through conductor 134, contact members of relay 32 (now closed) conductor 135, contact members of relay 50, conductor 1B6, coil 2w of relay 2L, conductor 142, contact members 0 of relay GR3, and conductor 143 to supply conductor L2.

Thus, when the elevator car attains a position hithe hatchway in which the relay 2L is adjacent the inductor plate 2U, the relay is actuated to separate contact members 2UL, in the manner previously described.

The opening of the switch, comprising the contact members 2UL opens the circuit, previously traced, forenergizing relay 36.

The deencrgization of relay 36 causes the contact members a, b and c of the relay to open. The opening of the contact members a of relay 36 pens the short-circuit connection around the resistor R2 in the circuit or the field winding GF or thegenerator G and thus effects a further reduction in the generated voltage with a consequent reduction in the speed of the motor M and the speed of the travel or the elevator car.

The contact members b when opened, open the circuit, previously traced, for maintaining the door operating relay 45 energized. The deenergization of relay 45 effects the reclosing of contact members c and d thereof, whereby the door motor 10 is energized to effect the opening of the elevator car gate and hatchway door for the floor at which it is desired that the car should stop. It will thus be understood that the car gate and hatchway door start to open before the elevator ear is completely stopped so that no unnecessary time is wasted in opening the gate and door after the car is stopped.

The contact members 0 of relay 36 when opened. upon the ctrcuit previously traced, Ior energizin: thecmirlng coils Uw and Dw of the stopping mttoheeUL and DL, respectively. The deenergization of the coil Uw is without immediate effect with respect to effecting a separation of the contact members ULl and UL2, because the elevator car has, by this time, attained a position in the hatchway in which the roller Ur on the switch UL engages the raised surface of the cam 1U.

0n the other hand, the dcenergization oI the coil Dw of the switch DL effects a separation of the contact members DLl and D112, because in the position in which the elevator car is at this time, the roller Dr on the operating arm Do 01 the switch DL does not engage the raised surface of the cam 1D. Therefore, separation of the contact members DLl and D112 is effected by the biasing spring Dd of the switch. However, the separation of the contact members of the switch DL is of no effect, at this time, because they are not associated in an effective operating circuit.

When the hatchway door and car gate interlock switches d and g, respectively, are opened by the hatchway door and car gate, the circuit, previously traced, for energizing the coil of relay 33, is opened and the relay 38 deenergized to open its contact members. The opening of the contact members of relay 38 is of no effect at this time. because the circuits for energizing the coils of all of the relays, which circuits include the contact members of relay 38, have been previously opened, as above described.

When the elevator car attains a position substantially at the level of the ficor at which it is to stop, the roller Ur rolls off the raised surface of the cam Ill and a separation of the contact members ULl and U12 on the contact arm Us from the stationary contact members ULl and UL2, respectively, is effected.

The separation of the contact members UL. opens the circuit which was previously main-- tained thereby for energizing the coils of relays l, 3 and 5 and these relays are thus respectively deenergized.

Deenergization of relay 5 opens its contact members a and b. The opening of the contact members aof relay 5 removes the short-circuit connection around resistor 1'1 in the circuit for energizing the field winding M of the motor M and the addition of this resistance in the field circuit causes the field current through the field winding M! to be decreased.

The opening of contact members I) of relay 5, opens the circuit; previously traced, for energizing the coil of relay GRl, which effects the reclosing of the contact members of that relay. The closing of the contact members of relay CIR-1. conn. its the demagnetizing field. winding GAF across the terminals of the generator armature windin: GA in series with the limiting resistor R.

The deenergization of the relays 1 and 3 causes the contact members of the respective relays to open except for contact members (Z of relay 1 which close. The opening of the contact members of relay 3 and the opening of contact members a of relay 1 open the circuit. previously traced, for energizing the field winding GF of the generator G.

The opening of contact members c of relay 1 opens the circuit, previously traced, for energizing relay FRI and the contact members thereof are thus caused to open and remove the short-circuit connection around the resistor T2. The re-inscrtion of the resistor T2 in the circuit of the field winding M! of the motor M causes the field current therethrough to be reduced to a minimum so that the power consumption in the field winding My is a minimum, while the motor M is stopped as it immediately is in the manner hereinafter described.

The opening of contact members b of relay 1 opens the circuits previously traced, for effecting the energization of the holding coil 7H of relay 7, the brake solenoid Bs, the coil of relay 32 and the coil of relay 55. The relay 7 has been maintained in its actuated position up to this time by the force exerted by the holding coil 7H, although the pick-up coil 7P was deenergized due to the fact that the circuit for energizing it was opened'by the separation of the contact members ULZ.

However, although the contact members I) of relay 7 have opened, the coil 7H and the brake solenoid Bs do not immediately deenergize because of the circulating current discharged through the shunt resistor 3R, as previously described.

The deenergization of relay causes the contact members a and 0 thereof to open and the contact members 19 thereof to reclose. The resistors R3 and R4 are thus rendered in condition tobe short-circuited during a subsequent acceleration period by the closing of contact members a of relay (3R3. The holding circuit maintained by the contact members c of relay 55 is thus interrupted but such interruption is without effect because the coil of relay 55 has already been deenergized by the opening of contact members b of'relay l.

' Deenergization of relay 32 causes the contact members thereof to open and interrupt the circuits for energizing the coils of the inductor relays 2L, 3L and 4L. Thus it will be seen that the power consumed by the coils of the inductor relays is a minimum in that the coils are energized only at times when their energization is required.

While the discharge current is circulating through the coil 7H of relay 7 and the brake solenoid Be and gradually dying out, the brake B is gradualy applied to the motor M. The relay '7 returns to its deenergized position, that is, the contact members thereof open, when the current through the holding coil 7H dies out completely.

The voltage generated by the generator G is reduced substantially to zero, due to the effect of the demagnetizing winding GAF, by the time that the contact members of relay '7 open and, therefore, the opening of the contact members a of relay 7 takes placewithout appreciable arcing. Fitting of the contact members a of relay 7 is thus prevented. The opening of contact members a, of course, interrupts the loop connection between the generator armature winding Ga and the motor armature Winding Ma and the motor M thus comes to a complete stop. The elevator car, at this time, is at the correct stopping level with the floor of the elevator car accurately in alignment with the floor of the building at which the car is stopped.

Theopening of contact members b of relay '7 opens the circuit for energizing relay 8. The deenergization of relay 8 causes the contact members of that relay to open and remove the short-circuit connection across the resistor R1 in series with the generator field winding GF. Obviously, such an addition of resistance in the field circuit of the generator is of no effect at this time because the field winding GE is already deenergized. However, the removal of the shortcircuit from the resistor R1 renders all of the resistors R1, R2, R3, R4 and R5 eflective to limit the subsequent initial energization of the elevator to the preenergi zati'ori value as above pointed out.

The voltage responsive relays 35 and 31 are respectively deenergized as the voltage impressed across the motor armature winding Ma decreases during the deceleration cycle and the contact members thereof are respectively opened as a result.

The elevator car is now properly stopped, the gate on the car and the hatchway door at the floor are both open and the passengers desiring to do so, may leave the car.

As previously mentioned, the leveling mechanism disclosed in Fig. 1, in addition to causing the car to continue in motion until the car is accurately leveled with the landing, is also effective to return the car to the floor landing, in the event of an overrun, or in the event that, after having been initially stopped level with the iioor, the car drifts away from the floor.

Assuming, for example, that, after having been stopped level with the floor landing in the abovedescribed manner, the elevator car moves to a position slightly above the floor landing, in response to the removal of a load therefrom, the contact members DL1 and DL2 of down direction leveling switch DL are moved to a closed position. Closure of contact members DL1 completes a circuit for relays 4, 2 and 5, which extends from line conductor L1 through contact members DL1, contact members at of relay 1, and

thence to line conductor L2 through the coils 4,'

2 and 5. Closure of contact members DL2 completes a circuit for the actuating coil ll of relay '7, which extends from line conductor Llthrough conductor 97, coil 7P, and thence to line conductor L2 through ocntact members DL2.

Relay 5 functions, as in the previously described operation, to increase the excitation of the motor field winding mi and to complete a circuit for the demagnetizing field 'contactor (3R1. I

Relays 2 and 4 in closing function to connect the generator field winding GP across line conductors L1 and L2, the connections'being the reverse of those provided by relays l and 3 described above.

Relay 7 in closing connects the armatures of motor M and generator (3-, inthe manner previously described.

Relays 4 and '7 in clos'mg also complete circuits for the release coil Bs of the electromagnetic brake for the holding coil 7H of relay '7 and for the coils 32 and 8, which elements func- 'tion' as in the previously described example.

Relay 2 in closing also completes a circuit for field relay FRI, which closes to increase the excitation of the motor field winding to the maximum value.

Upon completion of the above circuits, motor M is caused to move the elevator car downwardly at the lowest or minimum operating speed. When the car reaches a position substantially level with the floor landing, roller Dr passes out of engagement with cam 11) and contact members DL1 and D12 reassuming the open position.

The opening of contact membersDLl interrupts the circuit for relays 4, 2 and 5, and the opening of contactmernbersDLZ interrupts the It may happen, under some circumstances,

CTl

its

that the car passes beyond a floor level in connection with the initial stopping operatiomin which event a return movement is immediately necessary. A releveling operation under these condltlons is identical with the releveling operatlon Just described, with the exception that the reverse movement of the car may be initiated before the holding coil 7H releases relay 7. In this event. the electromagnetic brake is not applied, nor is the armature circuit of motor M interrupted until the leveling movement is terminated.

It will be observed that releveling movements in either direction may be effected regardless of the position of the doors, since contact members ULZ and DL2 and the leveling switches UL and DL, respectively, complete circuits for the coil 1? of relay '7, which are independent of the contact members of relay 3B.

The subsequent operation of the elevator for the up? direction of movement of the car is the as previously described except that for. runs between two adjacent doors the voltage generated by the generator G is insuflicient to actuate the voltage responsive relays and 31 and, therotore, high speed operation cannot be attained.

The operation 0! the control system for down travel of the elevator car is substantially similar to that already described and a detailed explanation and tracing oi clrcuitsls deemed un- ,It will, therefore, be seen that I have devised an elevator control system comprising means for substantially reducing the time interval between the closure of the elevator car gate and hatchway door interlock switches and the actual starting movement of the elevator car with the result that a greater cmciency and speed of operation of the elevator systemic obtained.

It will be soon also, that I have devised an elevator control system comprising a novel comhination of elements including a Ward-Leonard system and a car switch for controlling switchin: connections for the generator field independently 0! whether or not the door and gate interlock switches for the elevator ,are closed, the car switch also controlling switching conmentions between the armatures of the generator and motor but only when the door and gate inbrlook switches for the elevator are closed.

It will be seen, further, that I have provided I novel combination of elements including the above car-switch control of the switching conitectlons ot the generator field and the switching connections between the armatures of the generatorand motor and a control of both of the switching connections by a levelling mechanism independently of whether or not thetdoor and we interlock switches for the elevator are closed. a l furthermore, it will be seen that Iv have providsd an elevator control system including means the field of a generator of a Ward- M d system to a predetermined value before me closing 01 the door and gate interlock switches tor the elevator, which predetermined value is diflerent than the value thereof at the time of starting movement 01' the elevator car when the interlock switches are closed.

It should be understood that my invention has been described specifically with reference to a variable-voltage or Ward-Leonard system merely for purposes of illustration, and that it is capable or application to other types 01 motor control watoms as well as or various modifications without a departure from the spirit and scope thereof. It is intended therefore, that no lim itations be imposed thereon except such as are necessitated by the prior art and by the scope of the appended claims.

I claim as my invention:

1. In a control system for an elevator car, a motor for driving said car, a generator for supplying power to said motor, switching means actuable to complete a circuit including the armatures of said motor and said generator whereby said generator supplies power to said motor, and control means for said car including means for causing said generator to induce a predetermined voltage prior to the actuation of said switching means.

-2. In a control system for an elevator car, a motor for driving said car, a generator for supplying power to said motor, switching means actuable to complete acircuit including the armatures of said motor and said generator whereby said generator supplies power to said motor. and control means for said car, including startin means for said car for causing said generator to induce a predetermined voltage prior to the actuation of said switching means.

3. In an elevator system, an elevator car movable in a hatchway, a door for said elevator car operable to an open and a closed position, a motor for driving said car, a generator for supplying power to said motor, switching means actuable to complete a circuit including the armatures of said motor and said generator whereby said generator supplies power to said motor, an interlock responsive to the position of said door for controlling the actuation of said switching means. and control means for said car, including means for causing said generator to induce a predetermined voltage regardless of the position of said door.

4. In an elevator system, an elevator car movable in a hatchway, a door for said car operable to an open and a closed position, a motor for driving said car, a generator for supplying power to said motor, switching means actuable to complete a circuitincluding the armatures of said motor and said generator whereby said generator supplies power to said motor, and control means for said car, including means for effecting the actuation of said switching means only when said door is substantially closed, and means for causing said generator to induce a predetermined voltage regardless of the position of said door.

5. In. an elevator system, an elevator car movable in a hatchway, a door for said elevator car operable to an open and a closed position, a motor for driving said car, a generator for supplying power to said motor, switching means actuable to complete a circuit including the armature of said motor and said generator whereby said generator supplies power to said motor, control means for said car, including starting means operable to cause said generator to induce a predetermined voltage regardless of the position of said door, and means for preventing the actuation of said switching means unless said door is substantially closed.

6. In an elevator system, an elevator car movable in a hatchway, a door for said elevator car operable to an open and a closed position, a motor for driving said car, a generator for supplying power to said motor, a field winding for said generator, switching means actuable to complete a circuit including the armatures of said motor and said generator whereby said generator supplies power to said motor, switching means actuable to connect said generator field winding to a source of power whereby the winding is energized, control means for said car, including means for effecting the actuation of both of said switching means, and means for preventing the actuation of said first mentioned switchin means thereby unless said door is substantially closed, the actuation of sa d second mentioned switching means being el'iected regardless of the position of said door.

7. In an elevator system, an elevator car movable in a hatchway, a door for said elevator car operable in an open and a closed position, a motor for driving said car, a generator for supplying power to said motor, a field winding for said generator, switching means actuable to complete a circuit including the armatures of said motor and said generator whereby said generator supplies power to said motor, switching means actuable to connect said generator field winding to a source of power whereby the winding is energized, control means for said car, including starting means i or said car for effecting th actuation of both of said switching means, and means for pr venting the actuation of said first mentioned switching means by said starting means unless said door is substantially closed, the actuation of said second mentioned switching means being effected regardless of the position of said door.

8. In an elevator system, an elevator car movin a hatchway, a door for said elevator operble to an open and a closed position, a motor or .riving said car, a generator for supplying ower to said motor, switching means actuable to complete a circuit including the armatures of said motor and said generator whereby said generator supplies power to said motor, control means for said car, including starting means for said car operable to effect the closing of said door and to cause said generator to induce a predetermined voltage before the said door attains a substantially closed position, and means for preventing al actuation of said switching means unless said door is in a substantially closed position.

9. In an elevator system, an elevator car movable in a hatchway, a door for said elevator car operable to an open and a closed position, a motor for driving said car, a generator for supplying power to said motor, switching means actuable to complete a circuit including the armatures of said motor and said generator whereby said generator supplies power to said motor, control means for said car, including starting means for said car operable to effect the closing of said door and to eiTect the actuation of said switching means, means for preventing the actuation of said switching means by said starting means unless said door is in a substantially closed position, said starting means also being operable to cause said generator to induce a predetermined voltage before the said door attains a substantially closed position. 7

10. In an elevator system, an elevator car movable in a hatchway, a door for said elevator car operable to an open and a closed position, a motor for driving said car, a generator for supplying power to said motor, a field winding for said generator, switching means actuable to complete a circuit including the armatures of said motor and said generator whereby the said generator supplies power to said motor, switching means actuable to connect said generator field winding to a source of power whereby the winding is energized, control means for said car, including starting means for said car for effecting the closing of said door and the actuation of both of said switching means, and means for preventing the actuation of said first mentioned switching means by said starting means unless said door is substantially closed, the actuation of said second mentioned switching means being effected regardless of the position of said door.

11. In an elevator system, an elevator car, a door for said car operable to an open and a closed position, a motor for driving said car, a generator for supplying power to said motor, switching means actuable to complete a circuit including the armatures of said motor and said generator whereby said generator supplies power to said motor, starting means for said car operable to effect the actuation of said switching means, means for preventing the actuation of said switching means by said starting means unless said door is in a substantially closed position, means operably responsive to the operation of said starting means for causing said generator to induce a predetermined voltage regardless of the position of said door, and levelling means for i said car operable to control said switching means and cause said generator to induce voltage regardless of the position of said door.

12. In an elevator system, an elevator car, a door for said car operable to an open and a closed position, a motor for driving said car, a generator for supplying power to said motor, a field winding for said generaton'switching means actuable to complete a circuit including the armatures of said motor and said generator whereby said generator supplies power to said motor, switching means actuable to connect said generator field winding to a source of-power whereby the winding is energized, control means for controlling both of said switching means, including starting means for said car operable to effect the actuation of both of said switching means, means for preventing the actuation of said first mentioned switching means by said starting means unless said door is in a substantially close position, the actuation of said second mentioned switching means being effected regardless of the position of said door, and levelling means for said car for controlling both of said switching means regardless oi the position of said door.

13. In an elevator system, an elevator car, a door for said car operable to an open and a closed position, a motor for driving said car, a generator for supplying power to said motor, a field winding for said generator, switching means actuable to complete a circuit including the armatures of saidmotor and said generator whereby said generator supplies power to said motor, switching means actuable to connect said generator field winding to a source of power whereby the winding is energized, control means for controlling both of said switching means, including starting means for said car operable to effect the actuation of both of said switching means, means comprising interlocking means controlled by said door for preventing the actuation of said first mentioned switching means by said starting means unless said door is substantially closed but the actuation of said second mentioned switching means by said starting means being eifected regardless of the position of said door, and means for stopping said car including levelling means for said car for controlling both of said switching means regardless of the position of said door.

14, In a, control system for an elevator car, a

motor for driving said car, a generator for supplying power to said motor, switching means actuable to complete a circuit including the armatures of said motor and said generator whereby said generator supplies power to said motor, control means for said car, including means for effecting the actuation of said switching means, means for controlling said generator to cause it to induce a predetermined voltage prior to the actuation of said switching means, and means including means operably responsive to the actuation of said switching means for causmg said generator to induce a voltage diilerent said predetermined voltage.

15. In a control system for an elevator car, a motor for driving said car, a generator for supplylng power to said motor, a field winding for said generator, switching means actuable to complete a circuit including the armatures of said motor and said generator whereby said generator supplies power to said motor, switching means actuable to connect said generator field winding to a source of power whereby the said winding is energized, control means for said car, including starting means for effecting the actuation of both of said switching means, means for effecting the actuation of said second mentioned switching means by said starting means before said first mentioned switching means is actuated, means for limiting the energization of said field winding to a predetermined degree upon the actuation of said second mentioned switching means, and means including means operably responsive to the actuation of said first mentioned switching means for effecting the energization of said field windingto a degree different than said predetermined degree.

16. In a control system for an elevator car, a door for said car operable to an open and a closed position, a motor for driving said car, a generator for supplying power to said motor, a field winding for said generator, switching means actuable to complete a circuit including the armatiires or said motor and said generator whereby said generator supplies power to said motor, switching means actuable to connect said generator field winding to a source of power whereby the said winding is energized, control means for said car, including starting means for effecting the actuation of both of said switching means, means for preventing the actuation of said first mentioned switching means by said starting means unless said door is in a substantially closed position, the actuation of said second mentioned switching means being effected regardless of the position of said door, means for limiting the energization of said field winding to a predetermined degree upon the actuation of said second mentioned switching means, and means including means operably responsive to the actuation of said first mentioned switching means for eflecting the energization of said field winding to a degree different than said predetermined degree.

17. In a control system for an elevator car, a door for said car operable to an open and a closed position, a motor for driving said car, a generator for supplying power to said motor, a field winding for said generator, switching means actuable to complete a circuit including the armatures of said motor and said generator whereby said generator supplies power to said motor, a switching means aotuable to connect said generator field winding to a source of power whereby the said winding is energized, control means for said car, including starting means for effecting the actuation of both of said switching means, means for preventing the actuation of said first mentioned switching means by said starting means unless said door is in a substantially closed position, the actuation of said second mentioned switching means being effected regardless of the position of said door, means for limiting the energization of said field winding to a predetermined degree upon the actuation of said second mentioned switching means, and means including means operably responsive to a substantially closed position of said door for effecting the energization of said field winding to a degree different than said predetermined degree.

18. In a control system for an elevator car, a door for said car operable to an open and a closed position, a motor for driving said car, a generator for supplying power to said motor, a field winding for said generator, switching means actuable to complete a circuit including the armatures of said motor and said generator whereby said generator supplies power to said motor, switching means actuable to connect said generator field winding to a source of power whereby said winding is energized, control means for said car, including starting means for effecting the actuation of both of said switching means, means for preventing the actuation of said first mentioned switching means by said starting means unless said doorv is in a substantially closed position, the actuation of said second mentioned switching means by said starting means being eilected regardless of the position of said door, means operably responsive to a substantially closed position of said door for effecting the energization of said field winding to a predetermined degree correspending to the minimum speed of said car, and means operable to effect an energization of said field winding to a degree different than said predetermined degree before said door attains its closed position.

GEORGE K. HEARN. 

